Rotary drilling bit



Oc't. 20, 1953 T. A. WHITE Y ROTARY DRILLING BIT Filed Sept. l2, 1949 n Dlo been positioned over the upper portions of the cutter members the parts are rigidly secured together and the bit is in condition to withstand the twisting and shearing forces to which it is subjected during the drilling operation. Moreover, the longitudinal edgesof the cutter members readily come into intimate contact under the twisting force required to rotate the drill, and serve to give added strength to the structure to withstand the force applied to the bit during the drilling operation.

It will be noted that the teeth 32 of the cutters extend laterally somewhat beyond the winglike portions 34, 36 and 38 of the cutter members thus assuring that the body of the bit will clear the wall of the bore, and also tending to produce a clean, full-gauge hole. The Avertical edges of the outermost teeth 32, as well as the vertical edges of the wing-like portions 34, 36 and 38,'

may, of course,be provided with hardened surfaces,'or coated with a suitable hard metal alloy if desirable.

As best seen in Fig. 4, the lug 44 is disposed opposite the wing-like portions 34, 35 and 38, so that the greatest thickness of the cutter mem-l bers is in the region where the lugs are located, thus serving to substantially reinforce the parts where the maximum strength is needed. The parts of the rotary drilling bit are preferably of steel and may be conveniently made in the form of castings.

In assembling the bit structure described above, the cutter members are positioned about the bowl I6, with the lugs 44 and 48 extending into the holes 42 and recesses 46, respectively, andthe tapered collar 20 is positioned over the upper end portion I8 of the cutter members, to retain the same in assembled position about the bowl. The drill collar 22 is then screwed onto the upper threaded end portion 24 of the bowl, into engagement with the upper end of the tapered collar, to force the same into close contact with the cutter members, thus locking the same securely in position. The bit may then be connected to a drill stem of conventional.

structure by means of the drill collar 22 or otherwise.

Upon rotation of the bit the cutting edges of the teeth 23 are the first to engage the material which is being drilled, and the outwardly and upwardly stepped teeth 30 and 32 are subsequently brought into operation. Moreover, the' bit thus cuts the material over relatively small areas at slightly diierent levels, and is therebyv effective for rapid drilling through various types of materials with a minimum expenditure of power and strain on the drill structure. The

very small. core produced by the spacing of the inner extremities of the cutters forms no substantial obstruction, and readily crumbles or breaks away as the drilling progresses. y

It will thus be seen that the invention provides a rotary drill bit of simple designand-f rugged construction, having no complicated parts likely to be expensive in manufacture, and

which may be assembled or disassembled with a rality of cutter body members surrounding said bit support member, each of said cutter body members having an arcuate inner face and an outside surface which extends downwardly and outwardly over said tapered portion of the bit support member, a cutter blade integral with each of said body members and projecting downwardly therefrom, pins, and holes receiving said pins, on and in said cutter body members and bit support member, for interlocking said cutter body members and bit support member against the tendency of said cutter blades to retrogress in a rotational sense on said bit support member or move axially of said bit support member under the. rotary and axial forces of drilling, sleeve means'having a tapered inside extending .downwardly and outwardly over the outsides of said cutter body members for restraining said cutter body members to said bit support member against fescape from the interlocked positions, 'and means connected to said bit support member for longitudinally thrusting said sleeve to the restraining position.

2. A rotary drill bit comprising a bit support member having a downwardly and outwardly tapered portion annular in cross section, a plurality of cutter body members surrounding said bit support member, each of said cutter body members having an arcuate inner face and an outside surface which extends downwardly and outwardly over said tapered portion of the bit support member, a cutter blade integral with each of said body members and projecting downwardly therefrom, longitudinally spaced pins, and longitudinally spaced holes receiving said pins, along each of said cutter body members and said bit support member for positively aligning said cutter body members and bit support member with respect to each other and interlocking the same against the tendency of said cutter blades to retrogress in a rotational sense on said bit support member or move axially of said bit support member under the rotary and axial forces of drilling, sleeve means having a tapered inside extending downwardly and outwardly over the outsides of said cutter body members for restraining said cutter body members to said bit support member against escape from the interlocked positions, andmeans connected to said bit supportrrnember for longitudinally thrusting'said sleeve ,tol the restraining psonf, THOMAS'A.'WHITE.

References cited in the me pf this patent u UNITED STATES PATENTS Number- Name Date 1,774,084- Cooney Aug. 26, 1930 1,843,136 Le Bus Feb. 2, 1932 1,878,292 Pivoto Sept. 20, 1932 1,940,890 Stokes Dec. 26, 1933 2,199,692` Catland May 7, 194.0 2,300,805 -Pew Nov. 3, 1942 2,498,251 'Creel Feb. 21, 1950 2,504,978- Henning Apr. 25, 1950 FOREIGN ,PATENTS Number Country Date 105,606 Germany Oct. 5,l 1899' OTHER REFERENCES Herb J. Hawthorne, Inc., Catalog No. 47-1, September 1946, page 2. 

